Defining the maximum extent of the Laurentide Ice Sheet in Home Bay (eastern Arctic Canada) during the Last Glacial episode

<p>The maximal extent and subsequent deglaciation of the Laurentide Ice Sheet (LIS) across eastern Baffin Island during the last glacial cycle (MIS-2) has been widely debated during the last decades as different palaeo-glaciological models have been proposed. Spatial and temporal variability of ice sheets extension during Quaternary glaciations complicate the establishment of a reliable reconstruction of the ice dynamics in the area. Furthermore, the lack of geophysical data in most of the fjords, and seaward, makes it difficult to reconcile the proposed terrestrial and marine glacial margins. High-resolution swath-bathymetric data, collected between 2003 and 2017, display a diversity of glacial bedforms in the Clyde Inlet fjord-cross-shelf-trough system (Eastern Baffin Island, Arctic Canada). These bedforms reveal a potential position of the LIS margin during the Last Glacial Maximum (LGM) near the shelf break. Early deglaciation of the Clyde Trough was marked by an initial break up of the ice sheet. This rapid retreat of the ice margin was punctuated by episodic stabilizations forming GZWs. This retreat was followed by a readvance and subsequent slow retreat of the LIS, as indicated by the presence of recessional moraines. Long-term stabilizations within the trough possibly coincided with major climatic cooling episodes, such as the end of Heinrich event 1 (H1) and the Younger Dryas. However, these stabilizations appear to have been influenced by topography, as GZWs can be found at pinning points in the trough. Deglaciation of the fjord occurred during the early Holocene and was faster, probably due to increased water depths. The presence of multiple moraine systems however indicate that deglaciation of Clyde Inlet was marked by stages of ice margin stabilization.</p>

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Sediment sources of northern Québec and Labrador glacial deposits and the northeastern sector of the Laurentide Ice Sheet during ice-rafting events of the last glacial cycle

Quaternary Science Reviews ◽

10.1016/j.quascirev.2009.08.008 ◽

2009 ◽

Vol 28 (27-28) ◽

pp. 3236-3245 ◽

Cited By ~ 9

Author(s):

Martin Roy ◽

Sidney R. Hemming ◽

Michel Parent

Keyword(s):

Ice Sheet ◽

Laurentide Ice Sheet ◽

Sediment Sources ◽

Glacial Cycle ◽

Glacial Deposits ◽

Last Glacial ◽

Ice Rafting ◽

The Last Glacial

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Laurentide Ice Sheet Meltwater and the Atlantic Meridional Overturning Circulation During the Last Glacial Cycle: A View From the Gulf of Mexico

Abrupt Climate Change: Mechanisms, Patterns, and Impacts - Geophysical Monograph Series ◽

10.1029/2010gm001016 ◽

2011 ◽

pp. 39-56 ◽

Cited By ~ 1

Author(s):

B. P. Flower ◽

C. Williams ◽

H. W. Hill ◽

D. W. Hastings

Keyword(s):

Gulf Of Mexico ◽

Ice Sheet ◽

Atlantic Meridional Overturning Circulation ◽

Meridional Overturning Circulation ◽

Laurentide Ice Sheet ◽

Glacial Cycle ◽

Overturning Circulation ◽

Last Glacial ◽

Meridional Overturning ◽

The Last Glacial

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Evolution of the large-scale atmospheric circulation in response to changing ice sheets over the last glacial cycle

Climate of the Past ◽

10.5194/cp-10-1453-2014 ◽

2014 ◽

Vol 10 (4) ◽

pp. 1453-1471 ◽

Cited By ~ 57

Author(s):

M. Löfverström ◽

R. Caballero ◽

J. Nilsson ◽

J. Kleman

Keyword(s):

Atmospheric Circulation ◽

Large Scale ◽

Ice Sheets ◽

Ice Sheet ◽

Laurentide Ice Sheet ◽

Glacial Cycle ◽

Mean Flow ◽

Geological Evidence ◽

Last Glacial ◽

The Last Glacial

Abstract. We present modelling results of the atmospheric circulation at the cold periods of marine isotope stage 5b (MIS 5b), MIS 4 and the Last Glacial Maximum (LGM), as well as the interglacial. The palaeosimulations are forced by ice-sheet reconstructions consistent with geological evidence and by appropriate insolation and greenhouse gas concentrations. The results suggest that the large-scale atmospheric winter circulation remained largely similar to the interglacial for a significant part of the glacial cycle. The proposed explanation is that the ice sheets were located in areas where their interaction with the mean flow is limited. However, the LGM Laurentide Ice Sheet induces a much larger planetary wave that leads to a zonalisation of the Atlantic jet. In summer, the ice-sheet topography dynamically induces warm temperatures in Alaska and central Asia that inhibits the expansion of the ice sheets into these regions. The warm temperatures may also serve as an explanation for westward propagation of the Eurasian Ice Sheet from MIS 4 to the LGM.

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Timing of advance and basal condition of the Laurentide Ice Sheet during the last glacial maximum in the Richardson Mountains, NWT

Quaternary Research ◽

10.1016/j.yqres.2013.06.001 ◽

2013 ◽

Vol 80 (2) ◽

pp. 274-283 ◽

Cited By ~ 22

Author(s):

Denis Lacelle ◽

Bernard Lauriol ◽

Grant Zazula ◽

Bassam Ghaleb ◽

Nicholas Utting ◽

...

Keyword(s):

Last Glacial Maximum ◽

Ice Sheet ◽

Glacial Maximum ◽

Laurentide Ice Sheet ◽

Last Glacial ◽

Glacial Chronology ◽

Northwestern Margin ◽

Richardson Mountains ◽

The Last Glacial ◽

Peel Plateau

This study presents new ages for the northwest section of the Laurentide Ice Sheet (LIS) glacial chronology from material recovered from two retrogressive thaw slumps exposed in the Richardson Mountains, Northwest Territories, Canada. One study site, located at the maximum glacial limit of the LIS in the Richardson Mountains, had calcite concretions recovered from aufeis buried by glacial till that were dated by U/Th disequilibrium to 18,500 cal yr BP. The second site, located on the Peel Plateau to the east yielded a fossil horse (Equus) mandible that was radiocarbon dated to ca. 19,700 cal yr BP. These ages indicate that the Peel Plateau on the eastern flanks of the Richardson Mountains was glaciated only after 18,500 cal yr BP, which is later than previous models for the global last glacial maximum (LGM). As the LIS retreated the Peel Plateau around 15,000 cal yr BP, following the age of the Tutsieta phase, we conclude that the presence of the northwestern margin of the LIS at its maximum limit was a very short event in the western Canadian Arctic.

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Asynchronous instability of NE ice streams of the Laurentide Ice Sheet recorded in the marine sediments of Labrador Sea during the last glacial cycle

10.5194/egusphere-egu2020-6774 ◽

2020 ◽

Author(s):

Harunur Rashid ◽

Mary Smith ◽

Min Zeng ◽

Yang Wang ◽

Julie Drapeau ◽

...

Keyword(s):

Ice Sheet ◽

Laurentide Ice Sheet ◽

Labrador Sea ◽

Glacial Cycle ◽

Ice Streams ◽

Last Glacial ◽

Ice Stream ◽

Cumberland Sound ◽

Detrital Carbonate ◽

The Last Glacial

<p>Hughes et al. (1977) hypothesized of a pan-Arctic Ice Sheet that behaved as a single dynamic system during the Last Glacial Maximum. Moreover, the authors suggested a nearly grounded ice shelf in Davis Strait implying that little or no exchange between Baffin Island and the Labrador Sea. Here we present data at 1-cm (<100 years) resolution between ~12 ka and 45 ka that shed light on the discharge from Hudson Strait and Lancaster Sound ice streams of the Late Pleistocene Laurentide Ice Sheet. A reference sediment core at 938 m water depth on the SE Baffin Slope was investigated with new oxygen isotope stratigraphy, X-ray fluorescence geochemistry, and 18 14C-AMS dates and correlated to 14 regional deep-water cores. Detrital carbonate-rich sediment layers H0-H4 were derived principally from Hudson Strait. Shortly after H2 and H3, the shelf-crossing Cumberland Sound ice stream supplied dark brown ice-proximal stratified sediments but no glacigenic debris-flow deposits. The counterparts of H3, H4, and (?)H5 events in the deep Labrador basin are 4&#8211;10 m thick units of thin-bedded carbonate-rich mud turbidites from glacigenic debris flows on the Hudson Strait slope. The behavior of the Hudson Strait ice stream changed through the last glacial cycle. The Hudson Strait ice stream remained at the shelf break in H3-H5 but retreated rapidly across the shelf in H0-H2 and did not deglaciate Hudson Bay. During this time, Cumberland Sound ice twice reached the shelf edge. In H3&#8211;H5, it remained at the shelf break long enough to supply thick turbidites. Minor supply of carbonate-rich sediment from Baffin Bay allows chronologic integration of the Baffin Bay and Labrador Sea detrital carbonate records, which is diachronous with respect to Heinrich events. The asynchrony of the carbonate events implies an open seaway through Davis Strait. Our data suggest that the maximum extent of ice streams in Hudson Strait, Cumberland Sound, and Lancaster Sound was neither synchronous.</p>

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Ice-age ice-sheet rheology: constraints from the Last Glacial Maximum form of the Laurentide ice sheet

Annals of Glaciology ◽

10.3189/172756400781820859 ◽

2000 ◽

Vol 30 ◽

pp. 163-176 ◽

Cited By ~ 26

Author(s):

W. Richard Peltier ◽

David L. Goldsby ◽

David L. Kohlstedt ◽

Lev Tarasov

Keyword(s):

Last Glacial Maximum ◽

Ice Sheet ◽

Greenland Ice Sheet ◽

Glacial Maximum ◽

Ice Age ◽

Laurentide Ice Sheet ◽

Last Glacial ◽

Flow Law ◽

The Last Glacial Maximum ◽

The Last Glacial

AbstractState-of-the-art thermomechanical models of the modern Greenland ice sheet and the ancient Laurentide ice sheet that covered Canada at the Last Glacial Maximum (LGM) are not able to explain simultaneously the observed forms of these cryospheric structures when the same, anisotropy-enhanced, version of the conventional Glen flow law is employed to describe their rheology. The LGM Laurentide ice sheet, predicted to develop in response to orbital climate forcing, is such that the ratio of its thickness to its horizontal extent is extremely large compared to the aspect ratio inferred on the basis of surface-geomorphological and solid-earth-geophysical constraints. We show that if the Glen flow law representation of the rheology is replaced with a new rheology based upon very high quality laboratory measurements of the stress-strain-rate relation then the aspect ratios of both the modern Greenland ice sheet and the Laurentide ice sheet, that existed at the LGM, are simultaneously explained with little or no retuning of the flow law.

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A numerical investigation of ice-lobe–permafrost interaction around the southern Laurentide ice sheet

Journal of Glaciology ◽

10.3189/172756500781832800 ◽

2000 ◽

Vol 46 (153) ◽

pp. 311-325 ◽

Cited By ~ 82

Author(s):

Paul M. Cutler ◽

Douglas R. MacAyeal ◽

David M. Mickelson ◽

Byron R. Parizek ◽

Patrick M. Colgan

Keyword(s):

Last Glacial Maximum ◽

Ice Sheet ◽

Surface Profile ◽

Glacial Maximum ◽

Laurentide Ice Sheet ◽

Ice Dynamics ◽

Last Glacial ◽

Glacier Ice ◽

The Last Glacial Maximum ◽

The Last Glacial

AbstractPermafrost existed around and under marginal parts of the southern Laurentide ice sheet during the Last Glacial Maximum. The presence of permafrost was important in determining the extent, form and dynamics of ice lobes and the landforms they produced because of influences on resistance to basal motion and subglacial hydrology. We develop a two-dimensional time-dependent model of permafrost and glacier-ice dynamics along a flowline to examine: (i) the extent to which permafrost survives under an advancing ice lobe and how it influences landform development and hydrology, and (ii) the influence of permafrost on ice motion and surface profile. The model is applied to the Green Bay lobe, which terminated near Madison, Wisconsin, during the Last Glacial Maximum. Simulations of ice advance over permafrost indicate that the bed upstream of the ice-sheet margin was frozen for 60–200 km at the glacial maximum. Permafrost remained for centuries to a few thousand years under advancing ice, and penetrated sufficiently deep (tens of meters) into the underlying aquifer that drainage of basal meltwater became inefficient, likely resulting in water storage beneath the glacier. Our results highlight the influence of permafrost on subglacial conditions, even though uncertainties in boundary conditions such as climate exist.

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